Array Index Out Of Bounds??

I've recently come upon a frustrating Array Index Out Of Bounds error when selecting any of the "calculations" to be applied to the entered values(maximum 1000 values). I suspect it to be a problem with the

values[(c+1)]

in the for loop.

I can't figure a way around this problem. Can someone offer up a tidbit? The code is below.

If you use count as an index into values in this loop, it will take you out of bounds, since the last index in values is (values-1). Using (count+1) as the index is just icing on the cake - it puts you out of bounds one iteration sooner.
The standard idiom for looping over all elements of an array is

You want to have yourself describing one level of logic at a time. If you're reading a cookbook, and it says "Take two onions. Check to see if the knife is sharp enough. If not, get out your whetstone. Lubricate your whetstone with the oil provided, or vegetable oil or WD-40. Holding the whetstone in your off hand, pull the knife from hilt to tip along the blade, with the blade at a 15 degree angle to the stone. Repeat two or three times. Turn your wrist to present to opposite side of the blade to the whetstones and again draw the knife from hilt to tip along the stone three times. Repeat, alternating sides, until the blade is sharp. Cut the onions in half and remove the outer peel...

At that point you've forgotten what you're cooking. Same with your program: with all that detailed logic in the case statement, it's hard to keep track of what it is we're actually trying to do.
Push the implementation details down into methods, and don't be afraid to sub out smaller parts of those into helper methods.